Multiprotocol antenna system for multiple service provider-multiple air interface co-located base stations

ABSTRACT

A radio access node is configured to digitize a first analog radio frequency signal in order to generate first digital data indicative of the first analog radio frequency signal and is configured to digitize a second analog radio frequency signal in order to generate second digital data indicative of the second analog radio frequency signal. The first analog radio frequency signal is broadcast from a first mobile unit using a first air interface. The second analog radio frequency signal is broadcast from a second mobile unit using a second air interface. The first and second digital data are transported from the radio access node to the base unit using a shared transport medium. The base unit is configured to produce information derived from the first digital data and the second digital data that is used in performing base station processing for the first mobile unit and the second mobile unit.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/433,771, filed Mar. 29, 2012, which is a continuation of U.S. patentapplication Ser. No. 13/033,337, filed Feb. 23, 2011, which issued asU.S. Pat. No. 8,160,570, which is a continuation of U.S. patentapplication Ser. No. 12/817,706 filed Jun. 17, 2010, which issued asU.S. Pat. No. 7,920,858, which is a continuation of U.S. patentapplication Ser. No. 11/098,941, filed Apr. 5, 2005, which issued asU.S. Pat. No. 7,761,093, which, in turn, is a continuation of U.S.patent application Ser. No. 09/818,986, filed Mar. 27, 2001, whichissued as U.S. Pat. No. 6,963,552, which claims the benefit of U.S.Provisional Application Ser. No. 60/192,186, filed on Mar. 27, 2000, allof which are incorporated herein by reference.

BACKGROUND

The wireless telecommunication industry continues to experiencesignificant growth and consolidation. In the United States, marketpenetration is near 32% with approximately 86 million users nationwide.In 1999 the total number of subscribers increased 25% over the previousyear, with the average Minutes of Use (MOU) also increasing by about 20%per user. If one considers growth in the digital market, in as short asthree years, the digital subscriber base has grown to 49 million users,or approximately equal to the installed number of users of analog legacysystems. Even more interesting is an observation by Verizon Mobile that70% of their busy hour traffic (an important system design parameter) isdigital traffic, although only approximately 40% of the total number oftheir subscribers are digital users. The Verizon Mobile observationindicates the digital subscriber will drive the network design throughits increasing usage, whereas the analog user is truly a passive“glovebox” subscriber.

Similar growth has been witnessed in other countries, especially inNorthern and Western Europe, where market penetration is even higher,approaching 80% in some areas, and digital service is almost exclusivelyused.

With the availability of Personal Communications Service (PCS)frequencies in the United States, and additional continuing auctions ofspectrum outside of the traditional 800-900 MegaHertz (MHz) radio band,the past few years have also seen increased competition among serviceproviders. For example, it has also been estimated that 88% of the USpopulation has three or more different wireless service providers fromwhich to choose, 69% have five or more, and about 4% have as many asseven service providers in their local area.

In 1999 total wireless industry revenue increased to $43 B, representingan approximate 21% gain over 1998. However, a larger revenue increasewould have been expected given the increased subscriber count and usagestatistics. It is clear that industry consolidation, the rush to buildout a nationwide footprint by multiple competing service providers, andsubsequent need to offer competitive pricing plans has had the effect ofactually diminishing the dollar-per-minute price that customers arewilling to pay for service.

These market realities have placed continuing pressure on systemdesigners to provide system infrastructure at minimum cost. Radio towerconstruction companies continue to employ several business strategies toserve their target market. One approach, their historical businessstrategy, is build-to-suit (i.e., at the specific request and locationas specified by a wireless operator). But some have now takenspeculation approach, where they build a tower and then work with localgovernment authorities to force new service providers to use the alreadyexisting towers. This speculation build approach, spawned by the zoningby-law backlash, is actually encouraged by communities to mitigate the“unsightly ugliness” of cellular phone towers. This is seemingly thebest alternative, since Federal laws no longer permit local zoningauthorities to completely ban the deployment of wireless infrastructurein a community. Often the shared tower facility is zoned far removedfrom residential areas, in more commercialized areas of town, alongheavily traveled roads, or in more sparsely populated rural sections.But providing such out of the way locations for towers often does notfully address each and every wireless operator's capacity or coverageneed.

Each of the individual wireless operators compete for the householdwireline replacement, and as their dollar-per-MOU is driven down due tocompetition in the “traditional” wireless space, the “at home” use isone of the last untapped markets.

As the industry continues to consolidate, the wireless operator willlook for new ways to offer enhanced services (coverage or products) tomaintain and capture new revenue.

Considering the trends that have appeared over recent years, when giventhe opportunity to displace the household wireline phone with reliablewireless service, a wireless service operator may see their average MOUsincrease by a factor of 2 to 4, thereby directly increasing theirrevenue potential 200 to 400%. In order to achieve this, the wirelessoperator desires to gain access throughout a community as easily aspossible, in both areas where wireless facilities are an allowed use andin where they are not, and blanket the community with strong signalpresence.

SUMMARY

Certain solutions are emerging that provide an alternative to the towerbuild out approach. In particular, wireless signal distribution systemsemploy a distribution media such as a cable television infrastructure oroptical fiber data network to distribute Radio Frequency (RF) signals.This allows the capacity of a single base station to be distributed overan area which is the equivalent of multiple traditional cellular siteswithout degradation in coverage or call quality.

However, even these systems have a shortcoming in that they aretypically built out for one selected over the air protocol and arecontrolled by a single service provider. Thus, even with such systems asthey are presently known, it becomes necessary to build out and overlaymultiple base stations and multiple signal distribution networks formultiple service providers.

The present invention is an open access signal distribution system inwhich a variety of wireless voice, data and other services andapplications are supported. The open access systems makes use of adistributed Radio Frequency (RF) distribution network and associatednetwork entities that enable the system operator to employ a wirelessinfrastructure network that may be easily shared among multiple wirelessservice providers in a given community. The open access system providesthe ability for such operators and service providers to share theinfrastructure regardless of the specific RF air interface or othersignal formatting and/or managing messaging formats that such operatorschoose to deploy.

In one configuration, the present invention consists of a system inwhich a base station interface located at a central hub locationconverts radio frequency signals associated with multiple base stations,of the same or even different wireless service providers, to and from atransport signaling format. A shared transport medium, such as a fiberoptic data network or the like is then used for transporting theconverted signals from the hub location to a number of remote accessnode locations.

The access node locations each have Radio Access Node equipment locatedtherein. The Radio Access Nodes (RANs) are each associated with aparticular coverage area. The RANs have within them a number of slicemodules, with each slice module containing equipment that converts theradio signals required for a particular service provider to and from thetransport signaling format.

In a preferred embodiment, the transport medium may be an optical fibertelecommunications network such as provided through the SONET typedigital frame formatting. In such a configuration, the SONET dataformatting is arranged so that certain data frames are associated withthe slices in a given Radio Access Node on a time slotted basis. In sucha configuration, signal down converter modules convert the radiofrequency signals associated with each base station to an IntermediateFrequency (IF) signal. Associated analog to digital (A/D) modules alsolocated at the hub then convert the Intermediate Frequency signals todigital signals suitable for handling by a transport formatter thatformats the converted digital signals to the proper framing format forthe SONET digital transport.

Other transport media may be used such as Internet Protocol (IP) overDigital Wavelength Division Multiplexing (DWDM).

In one other aspect the invention concerns the aggregation of differentRadio Frequency (RF) signaling formats onto a common transportmechanism. In this embodiment, a first and second base station operateaccording to respectively, first and second different wireless systemair interfaces. A transport medium interface converts the radiofrequency signals transmitted by the first and second base stations to acommon transport medium. The first and second base station mayoptionally also be operated under the control of two different serviceproviders. In this arrangement, a plurality of remotely located RadioAccess Nodes (RANs) each provide radio signal coverage to apredetermined portion of a total system coverage area. Each Radio AccessNode is coupled to receive signals from the common transport medium.Each Radio Access Node also contains a first and second slice moduleassociated with the respective one of the first and/or second basestation. Each slice module contains a suite of radio transmitter,amplifier and antenna equipment as required by its associated airinterface.

In another aspect the present invention concerns equalizing power levelsof Radio Frequency signals radiated by the Radio Access Nodes at levelsappropriate for respectively different air interfaces. In particular, insuch a system a first and second base station are located at a centrallocation and operate according to respectively different wireless systemair interfaces. A transport medium interface converts the RadioFrequency signals transmitted by the first and second base stations to acommon transport medium signaling format. At a plurality of remotelocations Radio Access Nodes (RANs) are located. Each Radio Access Nodeis coupled to receive signals from the common transport medium. EachRadio Access Node contains at least a first and second slice module thatis associated with and responsible for converting signals associatedwith the first and second base stations.

In this instance, the invention includes means for equalizing thereceive sensitivities of the Radio Access Nodes at levels for theappropriate for the respectively different air interfaces, such as bymanaging the number of RANs in simulcast depending upon the particularair interface.

This configuration permits for example, the deployment for the set ofshared RANs at common RAN remote locations without having to deploymultiple RAN locations for different air interfaces even when such airinterfaces have different receive sensitivities and coverage distances.Thus the Radio Access Nodes for two or more different air interfaces maybe co-located throughout the coverage system area reducing the overallsystem build out requirements.

In yet another aspect, the present invention is a method for providingaccess to radio equipment distributed throughout a coverage area tomultiple wireless communication service providers. This method involvesthe steps of accepting requests for radio signal distribution servicefrom the service providers, the request specifying a desired airinterface and an indication of which portions of a coverage area theparticular air interface is to be supported. The service provider theninstalls common base station equipment operating with the air interfacespecified by the service provider at a central location with the basestation equipment being co-located with base station equipment specifiedby other wireless service providers. The commonly located base stationequipment is then coupled to receive traffic signals from a signalingnetwork used by the wireless communication service provider, thesignaling network carrying such transport formatted Radio Frequencysignals over a common transport medium. A data processor then controlsthe connection of transport signal to specific Radio Access Nodes asspecified by the wireless system operator.

DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a block diagram of an open access system according to theinvention.

FIG. 2 illustrates one possible deployment for the open access system.

FIG. 3 is a more detailed diagram of a hub signal path for the openaccess system.

FIG. 4 is a more detailed diagram of a Radio Access Node signal path.

FIG. 5 shows one example of a calculation to determine how simulcastoperation can be coordinated to equalize a reverse link budget andprovide balancing with a forward link budget.

FIG. 6 is a more detailed view of a cross connect providing for theability to connect multiple base stations for different wirelessoperators to a network of Radio Access Nodes.

FIG. 7 is a diagram illustrating how RAN slices may be allocated todifferent tenants and sectors in simulcast.

FIG. 8 is a more detailed view of one possible configuration for thehubs and RANS over which both the transport traffic signals and controlsignaling may be carried.

FIG. 9 is a detailed view of one possible antenna configuration.

DETAILED DESCRIPTION

A description of preferred embodiments of the invention follows.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims. Turning attention now to thedrawings more particularly, FIG. 1 is a diagram of an open access system10. The open access system 10 is an open access network supporting amultitude of wireless voice, data, video services and applications.Wireless Service Providers (WSP) and Wireless Internet Service (WISP)Providers, commonly known as tenants, may use open access system 10 toeither enhance or replace existing networks, wired or wireless, or todevelop new networks.

Open access system 10 is a multi-frequency, multi-protocol RadioFrequency (RF) access network, providing cellular, PersonalCommunication Services (PCS), and wireless data coverage via adistributed RF access system. Open access system 10 is comprised of basestations 20, located at hub sites 30. The base stations 20 are connectedvia high speed datalinks 40 to distributed RF access nodes (RANs) 50.The system 10 is, in effect, a signal distribution network andassociated management entities that enable a network operator to deploya wireless infrastructure network that may easily be shared amongmultiple wireless system operators in a given community. The open accessnetwork may be shared regardless of the specific RF air interfaceformatting and management messaging formats that each wireless operatorchooses to deploy.

FIG. 2 depicts one possible deployment scenario for the open accesssystem 10. As shown, the system consists of a multiple Radio Frequency(RF) Access Node 50 (RAN) units that may be located at relatively lowerheight locations such as utility poles. The open access network 10distributes RF signals to and from the RANs, using a shared transportmedia 40 such as an optical fiber using high speed transport signaling.The physical deployment of the open access system is thus quitedifferent from the higher radio towers required in a conventionalsystem.

Returning attention to FIG. 1, the hub 35 provides the hardware andsoftware interfaces between the high speed data link 40 and theindividual wireless carrier base stations 20. The base stations 20 areconsidered to be original equipment manufacturer (OEM) type equipment tobe provided and/or specified by the tenant 15 and are not provided aspart of the open access system 10 itself. Hub 35 co-locates with thebase stations 20 at a designated hub site 30. In a maximumconfiguration, a 3-sector base station 20 connects to 24 RAN Units 50,via an open access Hub 35. Hub 35 can be expanded to connect multiplebase stations 20 (one or multiple wireless carriers) and theirassociated RAN Units 50.

RAN units 50 are distributed throughout a given community in accordancewith the network operator's RF plan. RAN Units 50, along with associatedantennas 56, are typically/installed on utility poles 58, and connect toHub Unit 35 via a fiber optic cable 40.

Network Management System 60 provides remote monitoring and control ofthe open access network by the network operator via the open accesssystem 10. Network Management System 60 also allows for the networkoperator to pass selected control or status information concerning theopen access network 10 to or from the individual wireless carriers ortenants. By “tenant” it is meant to refer to the wireless carrier,Wireless Service Provider (WSP), or other business entity that desiresto provide wireless service to end customers.

The open access system 10 supports essentially any wireless protocol tobe an open Access platform. In one configuration, open access system 10supports the multiple 800/1900 MHz wireless service providers, andwireless data providers who require last mile access to their targetedcustomers, all at the same time. In another configuration, open accesssystem 10 supports the lower frequency 400 and 700 MHz bands and theWCS/ISM/MMDS, U-NII wireless data bands.

In a preferred configuration, the open access network consists of radioaccess nodes (RAN) 50 distributed to achieve the desired RF signalpresence and a hub 35 and high speed data link 40, which interconnectsthe base station RF signals with the RANs 50.

The distributed architecture is comprised of multi-protocol,frequency-independent radio access nodes 50. In the preferred embodimentat the present time, each RAN 50 supports from 1 to 8 operators,commonly referred to as tenants 15, of various protocols andfrequencies. It should be understood that other configurations couldsupport a smaller or greater number of tenants per RAN 50. Within eachRAN 50, the wireless service provider “tenants” have typically leasedspace for the service provider to install corresponding individual radioelements in a RAN slice 52. RANs 50 connect to a centralized basestation locale 30 where the tenants 15 connect to through an open accessHUB 35 to the specific tenant's base station electronics. Each HUB 35can scale to support one to three sectors of a base stations 20. Itshould be understood that base stations with a greater number of sectors20 may also be supported.

RANs 50 are interconnected via fiber links 40 to centrally located HUBsites 30 and associated base stations 20. RANs 50 wide area distributionis logically a “horizontal tower” with access provided to a single“tenant” or shared amongst multiple tenants (wireless serviceproviders). The generic architecture supports scaling from a singleoperator to supporting up to multiple operators across the multiplefrequency bands per shelf. Multiple shelves may be stacked to serveadditional tenants, as needed.

HUB 35 and RAN 50 network elements incorporate a System NetworkManagement Protocol (SNMP) communication scheme to facilitateintegration with the Host operator's network management system 60. Thisallows easy and complete communication across the open access system 10with a high level of control and visibility.

Referring now to FIG. 3, an RF signal is transmitted from a BTS 20 toopen access hub 35. The RF signal is of any bandwidth up to typically 15MHz (future bandwidths may be greater) and follows the hub signal pathas shown in FIG. 3. The signal is down converted to a 50 MHz (+/−7.5MHz) Intermediate Frequency (IF) signal by the down converter (D/C) 100.The IF signal is then converted to a 14 byte stream, at least at 42.953Msps, by analog-to-digital (A/D) channelizer 102. Two control bits areadded to the stream at a field programmable gate array (FPGA) within theA/D channelizer 102. The 16 byte stream, still at 42.953 Msps, is thenserialized using 8B/10B encoding producing a 859 Mbps bit stream or anSTS-12 type transport signal. The STS-12 signal is then distributedalong a number of paths equal to the number of RANs in simulcast foreach BTS sector. The STS-12 signal is preferably transmitted to thedesignated RAN Units 50 by interconnect 106 cross-connecting the STS-12signal to a 4:1 multiplexer 108 that converts the STS-12 signal to anOC-48 signal. In a preferred embodiment, as shown in FIG. 1, a basestation 20 located at any hub site 30 can transmit its associated signalto any RAN Unit 50 using a digital cross-connect 37 connected betweenHubs 35. In one example, lower rate signals (STS-3, 4, etc.) may becombined into higher rate shared transport signals (e.g. OC-192).

Referring to FIG. 4, the OC-48 signal enters a multiplexer 108 where thesignal is converted from an OC-48 signal back to a STS-12 signal. TheSTS-12 signal is then digital-to-analog (D/A) converted to a 50 MHz(+/−7.5 MHz) signal by the D/A Channelizer 110. The 50 MHz (+/−7.5 MHz)signal is up converted 112 (U/C) to the required RF signal between. TheRF signal is then power amplified (PA) 114 at its associated RFfrequency and transmitted through diplexer 116 that couples transmit andreceive signals to the same antenna. The RF signal is then radiated bythe antenna.

Referring to FIG. 4, an RF signal is received by an antenna or antennaarray and the signal is then down converted (D/C) 100 to a 50 MHz(+/−7.5 MHz) signal. The RF signal is then converted to a 14 bit stream,at least at 42.953 Msps, in the (A/D) channelizer 102. Two control bitsare added to the bit stream at a digital filter implemented in a FieldProgrammable Gate Array (FPGA) within the A/D channelizer 102. The 16byte stream, at least at 42.953 Msps, is serialized using 8B/10Bencoding producing a 859 Mbps bit stream or STS-12 signal. The STS-12signal is then combined with the other tenant signals by a 4:1multiplexer 108 that converts the STS-12 signal to an OC-48 signal. Thissignal is then transmitted to the designated open access hub 35.

Referring to FIG. 3, the OC-48 signal is received at the open access hub35 at the multiplexer 108 that converts the OC-48 signal to a STS-12signal. The STS-12 signal is then cross-connected through interconnect106 to a designated BTS 20. The STS-12 signal is summed up to 8, 1 withsignals from other RANs in the same simulcast and is then D/A converted110 to a 50 MHz (+/−7.5 MHz) IF signal. It should be understood that inother configurations, more than 8 signals could be summed together. The50 MHz signal IF signal is the up converted (U/C) 112 to the desiredradio carrier and forwarded to the BTS 20. Providing for two receivepaths in the system 10 allows for receive diversity.

The location of the RANs will be selected to typically support radiolink reliability of at least 90% area, 75% at cell edge, as a minimum,for low antenna centerline heights in a microcellular architecture. Theradio link budgets, associated with each proposed tenant 70, will be afunction of the selected air protocol and the RAN 50 spacing design willneed to balance these parameters, to guarantee a level of coveragereliability.

Because of differences in air interface performance and mobile unittransmit powers/receive sensitivities the open access system 10 requiresadditional design considerations. For example, an optimal RAN locationgrid spacing for an IS-136 TDMA protocol is not the same as for an IS-95CDMA protocol.

To minimize the number of RANs 50, open access multi-protocol wirelessinfrastructure requires that all the participating wireless protocolsshare common geographic transmit/receive locations. These locations arereferred to as shared RANs 50, and the distance at which they can belocated from any serviceable mobile unit sets the nodes' maximumseparation. However, this distance limit is different for each wirelessprotocol due to performance differences in their respective airinterface power or link budgets. A simple, but non-optimum, approach isto determine the RAN 50 locations on the wireless protocol requiring theclosest spacing (i.e. smallest RF link budget). The base stations 20located at the central hub sites 30 are then optically connected to theco-located RAN sites 50 giving each protocol the same coverage footprintper base station sector. This approach is highly non-optimum for thoseprotocols having larger link budgets and will yield heavily overlappedcoverage areas. Similarly, basing RAN spacing on the larger link budgetwill yield coverage gaps for the weaker link protocols.

According to the present invention, differences between the wirelessprotocols' link budgets are equalized through simulcasting of multipleRANs sites 50. Simulcasting allows a wireless infrastructure provider toreduce the link budget of the RAN 50 for higher power protocols to matchthose of the others, while increasing the net coverage range of theassociated base station sectors 20. A reduction in a RANs 50 link budget(and therefore coverage range) is offset by the increase in the numberof RAN's 50 that can be simultaneously served by the associated basestation sectors 20. This maintains the base station 20 coverage area forthe protocols with a large link budget while maintaining the closer RAN50 spacing required for those protocols with a small link budget. At thesame time, the reverse link can be brought into balance with the forwardlink for a wide variety of forward RF carrier power levels.

FIG. 5 shows a simplified link budget for three example collocatedprotocols: IS-136 (TDMA), GSM 1900 and CDMA. It should be understoodthat the same principles apply to other wireless air interfaces such as:PEN, GSM, 3G (GPRS/EDGE), CDMA 2000, W-CDMA, etc. The protocol with thelowest intrinsic reverse link budget (IS-136) is balanced with the CDMAprotocol through the use of a larger number of RANs in the simulcastgroup for CDMA. All of the protocols' simulcast is also collectivelyscaled to balance with the forward link. For a higher-power deploymentthan is shown in FIG. 5 (similar to that of a large tower) the leastrobust air interface typically uses a simulcast of one and all other airinterfaces scale up from there. Since the illustrated scenario is for isa lower power microcellular build-out, all protocols use a non-unitysimulcast. The forward transmit powers for each RF carrier are properlyscaled to equalize the forward link budgets of the various protocols.Call capacity per geographic area is finally established by selectingthe number of RF carriers based upon the final simulcast ratio.

The determination of parameters may proceed as follows.

Forward and reverse RF link budgets are first established for each ofthe wireless protocols of interest. At this point, simulcast is notentered as a factor into the analysis.

The wireless protocol with the smallest link budget is then identifiedand its coverage area and capacity are optimized.

The system build-out, lower power (and smaller size) power amplifiersare used to minimize cost and size of the installation. Simulcast ofmultiple RANs 50 is used to bring the forward and reverse paths inbalance for the above identified wireless protocol. This establishes theallowable RF path loss and therefore the physical spacing for the sharedRANs 50.

For each of the other collocated protocols, the number RANs 50 insimulcast are selected to match the baseline link budget establishedabove. Each protocol will have a different simulcast number. Thesensitivity at each RAN 50 will change as 10 log₁₀ (the number of RANs50 in simulcast).

The forward transmit power levels are then adjusted to bring the forwardand reverse paths into agreement.

The number of simultaneous RF carriers is selected for each protocolbased upon the call capacity required in the geographic coverage area.Changing the number of carriers does not affect the link balance or thenumber of RANs 50 in simulcast.

Referring to FIG. 6, this type of infrastructure build-out requires adistributed RF system capable of cross-connecting multiple base stations20 from different tenants or Wireless Service Providers (WSPs) to anetwork of RANs 50 using distribution ratios that differ for eachwireless protocol. A network that does not support this aspect of theinvention would simply connect the base station sectors for all the WSPsto the same complement of RANs 50. Sector 1/WSP 1 through sector 1/WSP nwould all connect to the same RANs 50. Similarly, sector 2/WSP 1 throughsector 2/WSP n connect to a different but common group of RANs 50.

Referring to FIGS. 6 and 7, the system described by this inventionselects a different simulcast scheme for each individual sector of eachwireless operator and the total collection of RANs 50 distributedthrough a geographic coverage area. For example: Sector 1/WSP1 does notnecessarily connect to the same complement of RANs 50 as sector 1/WSP 2through sector 1/WSP n. There may be only partial or even no overlapbetween the connectivity assignments due to the variable simulcastratios across the differing protocols. Sector 2/WSP 1 not only does notfully overlap with sector 2/(WSP 2 through n) but also may alsopartially overlap with sector 1/(2 though n) in RAN assignments.

Referring in particular to the example shown in FIGS. 6 and 7, WSP ortenant 1 is operating with a CDMA protocol and therefore is simulcastinga group of 8 RANs within a total number of 24 RANs 50. Each RF sector isconnected to a different grouping of 8 RANs. The illustrated drawing inFIG. 8 is for a group of 24 contiguous cells showing how the threetenants may share them.

Tenant 2 is operating with a simulcast group size of 5. Thus 5 differentRANs are allocated to each of the 5 sectors for this tenant. Note thatsince simulcast number of 5 is not an integer divisor of the number ofcells in the RAN group, that number being 24 in this example, sector 3has only 4 cells allocated to it. Tenant 3 is operating with thesimulcast group size of 3 and thus is operating with 8 sectors, eachhaving 3 RANs associated with it.

The hub interconnect in FIG. 6 then selects RAN 50 simulcast groupingsfor each sector based upon the desired groupings desired for eachtenant. This permits for equalization of the radio frequency linkbudgets in each RAN 50 group.

NMS 60 distributes individual alarms to the appropriate tenants, andmaintains secure transmission for each tenant, whereas each tenant 15 isprovided access to only their own respective system, for monitoring andcontrol purposes. The open access product allows an operator tocustomize the RAN 50 RF parameter settings to control the radio linkenvironment, such as signal attenuation, gain, and other methods forstrong signal mitigation.

In sector configuration of the system, the Hub/RAN ratio is configurablefrom 1 to 8 RANs per BTS sector. The RANs 50 is remote configurablethrough the open access operator's NMS 60, to support what is commonlyreferred to as sector re-allocation. The sector allocation is defined bythe hosted wireless service provider's traffic loading analysis andcontrolled by the inputs from the specific tenant's NMS 15 via the openaccess system 10 intranet 18.

The actual RAN 50 cell radius will be largely a function of finalantenna radiation center above ground.

Returning attention now to FIGS. 1 and 2 briefly, in general, the datalink uses one or more fiber optic connections between a hub 35 and oneor more RAN's 50. Data link uses a mix of electrical multiplexing,wavelength multiplexing, and multiple fibers to support the bandwidthrequirements of the configuration in a cost-effective manner. Data linkdesign should optimize its cost by using the best combination ofdifferent multiplexing schemes based on physical fiber costs, leasedfiber costs and technology evolution. Data link supports whole RF bandtransportation (digitized RF), IP packets, and other traffic as need foropen access data transmission, system management and control.

The data link 40 connects a Hub 35 and multiple RAN's 50 using either aRing or Star network topology, or possibly a mix of the two. In oneconfiguration, open access system 10 should support up to, for either aring or star topology, at least several miles of fiber length. Theactual fiber lengths will be guided by optical path link budgets andspecific RF protocol limits.

Referring to FIG. 8, in addition to combining digitized RF for commontransport, this invention allows the combination of digitized RF withconventional packet data (e.g. IP Packets). This allows the concurrentsupport of packet driver wireless radios 59 co-located at the RANs withRAN slices 52, the latter which support BTSs 20. The data radios 59 donot require a BTS 20 at the hub.

The data link is available to support connecting fixed wireless dataradios 59 fitted in a RAN 50 to a centrally located router in HUB site30. In one configuration, IP packet traffic provides 10 Mbps, scalableup to 100 Mbps, to be shared amongst the multiple RAN data tenants.Networking architecture supports modularity and scalability forincreased data rates. The data link supports multiple data radios at 1to 25 Mbps data rates per data radio tenant.

Referring to FIG. 9, a utility pole antenna 86 is preferred as beingunobtrusive and similar in dimension to the utility pole 80. Antenna 86at least blends in with its immediate surroundings. The utility polemulti-band antenna 86 typically fits at least within a 12″ diameter by72″ tall volume. The minimum pole height to the antenna base istypically at least 31 ft. agl.

In the system the multi-band antenna capability addresses 800, 1900, andat least provides volume for wireless data bands. In a preferredconfiguration, the antenna is multi-band and provides radiating apertureto cover all the listed bands such as, 800, 1900, WCS/ISM/MMDS andU-NII. Antenna design, antenna sizing and performance is specific foreach deployment configuration.

The system configurations are modular and scalable from a single WSPapplication to a multi-WSP tenancy, for both the RF transceiverassemblies and the data link configurations. The system configurationshave the ability to add tenants after initial install in one-tenantsteps.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

What is claimed is:
 1. A method of distributing wireless radio frequency signals comprising: digitizing, at a radio access node using a first analog-to-digital converter, a first analog radio frequency signal in order to generate first digital data indicative of the first analog radio frequency signal, wherein the first analog radio frequency signal is broadcast from a first mobile unit using a first air interface; digitizing, at the radio access node using a second analog-to-digital converter, a second analog radio frequency signal in order to generate second digital data indicative of the second analog radio frequency signal, wherein the second analog radio frequency signal is broadcast from a second mobile unit using a second air interface; transporting the first and second digital data from the radio access node to a base unit using a shared transport medium; performing base station processing for the first mobile unit using information derived from the first digital data provided to the base unit; and performing base station processing for the second mobile unit using information derived from the second digital data provided to the base unit.
 2. The method of claim 1, further comprising down-converting a signal derived from the first analog radio frequency signal and down-converting a signal derived from the second analog radio frequency signal.
 3. The method of claim 1, further comprising: transporting, to the radio access node from the base unit, third and fourth digital data produced at the base unit; generating, at the radio access node, a third analog radio frequency signal from the third digital data using a third digital-to-analog converter in the radio access node, wherein the third analog radio frequency signal is generated in accordance with the first air interface; generating, at the radio access node, a fourth analog radio frequency signal from the fourth digital data using a fourth digital-to-analog converter in the radio access node, wherein the fourth analog radio frequency signal is generated in accordance with the second air interface; and radiating the third and fourth analog radio frequency signals in a coverage area associated with the radio access node.
 4. The method of claim 3, wherein generating, at the radio access node, the third analog radio frequency signal from the third digital data using the third digital-to-analog converter in the radio access node comprises up-converting a signal derived from the third digital data; and wherein generating, at the radio access node, the fourth analog radio frequency signal from the fourth digital data using the fourth digital-to-analog converter in the radio access node comprises up-converting a signal derived from the fourth digital data.
 5. The method of claim 1, the first and second analog radio frequency signals are in different radio frequency bands.
 6. The method of claim 1, wherein the first and second analog radio frequency signals are of different bandwidths.
 7. The method of claim 1, comprising communicating at least one of Internet Protocol (IP) packets and ETHERNET packets over the shared transport medium between the base unit and the radio access node.
 8. The method of claim 1, wherein the shared transport medium comprises an optical communication medium.
 9. A system for distributing wireless radio frequency signals, the system comprising: a base unit; and a radio access node located at a location that is remote from the base unit; wherein the radio access node is configured to digitize a first analog radio frequency signal in order to generate first digital data indicative of the first analog radio frequency signal, wherein the first analog radio frequency signal is broadcast from a first mobile unit using a first air interface; wherein the radio access node is configured to digitize a second analog radio frequency signal in order to generate second digital data indicative of the second analog radio frequency signal, wherein the second analog radio frequency signal is broadcast from a second mobile unit using a second air interface; wherein the first and second digital data are transported from the radio access node to the base unit using a shared transport medium; wherein the base unit is configured to produce information derived from the first digital data that is used in performing base station processing for the first mobile unit; and wherein the base unit is configured to produce information derived from the second digital data that is used in performing base station processing for the second mobile unit.
 10. The system of claim 9, wherein the system comprises a distributed antenna system.
 11. The system of claim 9, wherein the radio access node comprises: a first analog-to-digital converter to convert the first analog radio frequency signal in order to generate the first digital data indicative of the first analog radio frequency signal; and a second analog-to-digital converter to convert the second analog radio frequency signal in order to generate the second digital data indicative of the second analog radio frequency signal.
 12. The system of claim 9 further comprising a plurality of radio access nodes communicatively coupled to the base unit, wherein each of the plurality of radio access nodes is located at a respective location that is remote from the base unit; and wherein the system is configured to provide a total system coverage area, wherein each of the plurality of radio access nodes corresponds to only a respective portion of the total system coverage area.
 13. The system of claim 9, wherein the base unit is configured to transport, to the radio access node from the base unit, third and fourth digital data produced at the base unit; wherein the radio access node is configured to generate a third analog radio frequency signal from the third digital data using a third digital-to-analog converter in the radio access node, wherein the third analog radio frequency signal is generated in accordance with the first air interface; wherein the radio access node is configured to generate a fourth analog radio frequency signal from the fourth digital data using a fourth digital-to-analog converter in the radio access node, wherein the fourth analog radio frequency signal is generated in accordance with the second air interface; and wherein the third and fourth analog radio frequency signals are radiated in a coverage area associated with the radio access node.
 14. The system of claim 9, the first and second analog radio frequency signals are at least one of: (i) in different radio frequency bands; and (ii) of different bandwidths.
 15. The system of claim 9, comprising communicating at least one of Internet Protocol (IP) packets and ETHERNET packets over the shared transport medium between the base unit and the radio access node.
 16. The system of claim 9, wherein the shared transport medium comprises an optical communication medium.
 17. The system of claim 9, wherein the system is configured to distribute wireless radio frequency signals in a physical area in which multiple wireless service providers wish to provide service, wherein the base unit is located with a plurality of wireless base stations collocated at a hub location, the base stations receiving and transmitting radio frequency signals, with at least one of such base stations operating with radio frequency signals according to the first air interface and at least one of such base stations operating with radio frequency signals according to the second air interface; wherein the base unit comprises a base station interface configured to convert the radio frequency signals associated with the base stations to and from digitized versions thereof and for converting the digitized versions of the radio frequency signals associated with the base stations to and from a transport signaling format; wherein the system comprises a plurality of radio access nodes located remotely from the base unit and base stations, each of the radio access nodes associated with a respective partial coverage area corresponding to only a portion of a total system coverage area, wherein the radio access nodes are connected to the transport medium; and wherein each of the radio access nodes further comprises: a respective plurality of slice modules, wherein each of the respective plurality of slice modules has associated radio frequency signals formatted according to a selected one of the first and second air interfaces and comprises equipment configured to convert the associated radio frequency signals formatted according to the selected one of the first and second air interfaces to and from digitized versions thereof and to convert the digitized versions of the radio frequency signals formatted according to the selected one of the first and second air interfaces to and from the transport signaling format.
 18. A radio access node for use in a system for distributing wireless radio frequency signals, the radio access node comprising: an antenna interface to couple the radio access node to at least one antenna associated with the radio access node; a shared transport medium interface to couple the radio access node to a shared transport medium; and first and second analog-to-digital converters; wherein the radio access node is configured to use the first analog-to-digital converter to digitize a first analog radio frequency signal in order to generate first digital data indicative of the first analog radio frequency signal, wherein the first analog radio frequency signal is broadcast from a first mobile unit using a first air interface; wherein the radio access node is configured to use the second analog-to-digital converter to digitize a second analog radio frequency signal in order to generate second digital data indicative of the second analog radio frequency signal, wherein the second analog radio frequency signal is broadcast from a second mobile unit using a second air interface; wherein the radio access node is configured to transmit the first and second digital data to a base unit using the shared transport medium; and wherein the base unit is located at a location that is remote from the radio access node and is configured to produce information derived from the first digital data that is used in performing base station processing for the first mobile unit; and wherein the base unit is located at a location that is remote from the radio access node and is configured to produce information derived from the second digital data that is used in performing base station processing for the second mobile unit.
 19. The radio access node of claim 18, wherein the radio access node is configured to receive at least one of Internet Protocol (IP) packets and ETHERNET packets.
 20. The radio access node of claim 18, wherein the radio access node is configured to generate a third analog radio frequency signal from third digital data using a third digital-to-analog converter in the radio access node, wherein the third analog radio frequency signal is generated in accordance with the first air interface and the third digital data is produced at the base unit and transported to the radio access node; wherein the radio access node is configured to generate a fourth analog radio frequency signal from fourth digital data using a fourth digital-to-analog converter in the radio access node, wherein the fourth analog radio frequency signal is generated in accordance with the second air interface and the fourth digital data is produced at the base unit and transported to the radio access node; wherein the third and fourth analog radio frequency signals are radiated in a coverage area associated with the radio access node. 